Fine timing measurement (FTM) is applied to various fields in the modern science and technology, such as communications and positioning, and ranging. To prevent a measurement error caused by imprecise synchronization, in existing FTM measurement, measurement is performed using a method for measuring a time of flight of information in a one-to-one manner. A communications device and a response device that use the measurement method need to exchange information for multiple times, to learn of a distance between the communications device and the response device.